Climate action on CO2 emissions alone will not prevent extreme warming: study

The common goal of achieving “net zero” emissions most often refers to CO2 emissions alone.


To control climate change, the world must go beyond cutting carbon dioxide emissions and reduce lesser-known pollutants such as nitrous oxide that play a key role in global warming, new research has found.

Decades of global climate discussions have focused on CO2 emissions, which are most abundant in the atmosphere. The common goal of achieving “net zero” emissions most often refers to CO2 emissions alone.

Over the past year, more than 100 countries have pledged to reduce emissions of methane, another carbon-based greenhouse gas far more potent at trapping heat than CO2, by 30% by 2030. . Most of these countries have not yet indicated how they will meet this deadline.

Meanwhile, little attention has been paid to other warming pollutants, including black carbon, also known as soot, which absorbs radiant heat, as well as hydrofluorocarbons found in refrigerants and oxides of nitrogen. But along with methane, these pollutants are responsible for about half of the warming observed today, according to the study published Monday in the journal Proceedings of the National Academy of Sciences.

“When we worry about the short term…we need to look at other non-CO2 climate forcers,” said study co-author Durwood Zaelke, president of the Institute for Governance & Sustainable Development in Washington DC.

This is particularly important as countries seek to reduce their CO2 emissions by reducing their use of fossil fuels, still considered the main contributor to global warming. Using less fossil fuels will lead to less air pollution, including airborne sulfates that actually counteract some climate change by reflecting solar radiation away from Earth.

Scientists say these sulfates mask about 0.5 degrees Celsius of warming that would be seen without them, meaning aggressive climate action could temporarily raise temperatures – unless lesser pollutants are also addressed.

A decarbonization pathway alone would see the planet exceed 2 degrees Celsius warming above pre-industrial temperatures by 2045, according to the study.

Conversely, by controlling all climate pollutants together, the world could start avoiding some warming as early as 2030 and halve the rate of warming between 2030 and 2050, the results suggest.

“This landmark document should lead to a major overhaul” of global targets, said Euan Nisbet, a climatologist at Royal Holloway, University of London, not involved in the study. “If we don’t reduce non-CO2 warming as well, we’re cooking.”

(Except for the title, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Teresa H. Sadler